Most every fish in home aquaria are in a prison cell as we can't duplicate the millions of gallons of water and range that mother nature provides.
I'm also unclear about swimming in circles - do your fish swim at right angles? With proper filtration and constant water flow ie; a 55 gal sump I could keep an adult Oscar alive in a 10 gal tank. I think it would be cruel and unjust as a permenat home, however I've done it in "Hospital and Quarunteine" scenarios on several occassions. Filtration -Manually; changing the appropriate amount of water routinely - Biologically, removing the ammonia By-products,- Mechanically, moving the water across the atmosphere for gas exchange and to provide dissolved oxygen is always Key.